How important is it to feel like you belong?

Not feeling socially connected can make you stupider and lead to an early death:

When people’s sense of social connectedness is threatened, their ability to self-regulate suffers; for instance their IQ performance drops (Baumeister, Twenge, & Nuss, 2002). Feeling lonely predicts early death as much as major health risk behaviors like smoking (Cacioppo & Patrick, 2008).

Source: ” Mere Belonging: The Power of Social Connections” from Journal of Personality and Social Psychology